def f_dict():
    d = {'Michael': 95, 'Bob': 75, 'Tracy': 85}
    print(len(d))
    print(d['Bob'])
    d['Alince'] = 100
    print(d)

    d.pop('Alince')
    print(d)

    print(d.keys())
    print(d.items())


def f_set():
    '无序的不重复元素序列，不支持根据顺序获取元素'
    s = {1, 2, 3}
    print(s)

    s.add(2)
    print(s)

    s.add(6)
    print(s)

    s.remove(3)
    print(s)


# f_dict()
f_set()
